Chapter 40 Infectious Disorders

1. Chapter 40Infectious Disorders

2. Stages of infectious disease • Incubation period • Time between the invasion of an organism & the onset of S/S • 7-10 days (maybe longer depending upon pathogen) • Prodromal period • Time between the beginning of nonspecific symptoms & specific symptoms • Hours to a few days • Illness • Specific symptoms are evident • Convalescent period • Time between when the S/S begin to fade and a return to full wellness

3. Chain of infection • Reservoir • Place in which organisms grow & reproduce • Portal of exit • Method by which organisms leave an infected person’s body to be spread to another individual • Table 43-1 (blood, respiratory secretions, feces, & exudate from lesions) • Means of transmission • Direct contact, indirect contact, fomites (inanimate objects, ex. food, bedding, towels, combs, drinking glasses, etc), insects, or vermin • Portal of entry • Means by which a pathogen can enter an individual’s body • Inhalation, ingestions, breaks in the skin (ex. bites, abrasions, burns) • Susceptible host

4. VIRAL INFECTIONS • Viral exanthems (rashes) • Exanthem subitum (Roseola Infantum) • Rash following a high fever • Rubella (German measles) • Rarely seen because of MMR • Important because it can cause serious birth defects • Measles (Rubeola) • Rarely seen because of MMR • Occurs with Coryza (rhinitis and sore throat), cough, and conjunctiva • Koplik’s spots-whitish spots on the buccal membranes

5. Viral exanthems (rashes) • Chickenpox (Varicella zoster) • Will become rare because of mandatory immunization • Fluid filled vesicles that crust over, occur in different stages • Highly contagious, spread by respiratory droplets as well as contact • Herpes zoster • Same virus as chicken pox but usually occurs in older children/adults • Causes painful vesicles along a dermatome • May be treated with acyclovir • Erythema infectiosum (Fifth disease) • “slapped cheeks” appearance and a lacy rash • Important because it can cause birth defects • Smallpox (Variola) • Important because of bioterrorism • People with this are really sick with fever, chills, vomiting, then rash • Rash progresses from macule to papule to vesicle to pustule.

6. VIRAL INFECTIONS • Enteroviruses • Coxsackievirus infections • Herpangina • Poliovirus infections: Poliomyelitis • Occurs in other parts of the world • IPV used now instead of OPV because of immunocompromised people contracting disease shed in stool

7. Cytomegalovirus • Common cause of congenital infection in infants • Some children are asymptomatic for years and then manifest with • Mental retardation/learning disabilities • Hearing loss/blindness • Symptoms evident at birth can include • Jaundice • Seizures • Respiratory distress • microcephaly • Therapy is experimental

8. Viruses causing central nervous system diseases • Rabies • Other viral infections • Mumps • Rarely seen because of MMR • Mumps in a teenage or adult man can lead to sterility • Infectious mononucleosis • S/S similar to tonsillitis with sore throat, lymphadenopathy, and fever • Spleen is enlarged and fatigue can last ~6 weeks • Treat symptoms only

9. OTHER INFECTIONS • Scarlet fever • Group A beta-hemolytic strept • Often seen with Strept throat • Usually not seen with “cold” symptoms • Treated for 10-14 days with antibiotics • Eye infections/inflammations • Conjunctivitis (viral or bacterial) • Starts in one eye and moves to the other • Bacterial…purulent discharge • Viral…watery discharge • Schools or day care will only believe it is bacterial so treat with antibiotic ointment • Highly contagious, can be spread by gnats

10. OTHER BACTERIAL INFECTIONS • Anthrax • Important because of bioterrorism • Three types, inhalation, cutaneous, & gastro • Inhalation • Most serious, >90% mortality • Begins with flu like symptoms • Cutaneous • Begins as a papule and progresses to a painless depressed black eschar • Mortality 1% with antibiotic therapy • Gastrointestinal • Acquired by eating undercooked meat infected with anthrax • Develops abd. pain, diarrhea; mortality is 25% • Management • Cipro for >18 years, Doxycycline for <18.

11. Diphtheria • S/S • Foul nasal discharge, low-grade fever • Gray membranes on tonsils and pharynx • Neck edema • Therapeutic management • DTaP…rarely seen due to immunization • Pertussis • S/S • See Box 40-1 pg. 1034 • Therapeutic management • DTaP…rarely seen due to immunization

12. OTHER BACTERIAL INFECTIONS • Lyme disease • Transmitted by the deer tick • S/S • Papule at the site of the tick progressing to a large swollen ring • Systemic involvement • Therapeutic Management • Amoxicillin or PCN V or doxycycline • Prevention is the most important tool

13. OTHER INFECTIOUS PATHOGENS • Rickettsial diseases • Rocky mountain spotted fever • Transmitted by the wood, dog, or rabbit tick • S/S • A reddened area develops at the site of the tick bite • Afterwards, rash, headache, fever, and mental confusion • CNS involvement • Management • Tetracycline for 7-10 days • Prevention

14. OTHER INFECTIOUS PATHOGENS • Helminthic infections • Roundworms (Ascariasis) • Hookworms • Pinworms